Publication Date


Document Type


Committee Members

Elliott Brown (Advisor), Bruce Claflin (Committee Member), Jason Deibel (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)


In this thesis the characteristics of five bulk semi-insulated doped gallium nitride samples provided by Kyma Technologies, Inc were explored. The five GaN samples were grown on sapphire substrates by hydride vapor phase epitaxy (HVPE) and doped with different concentrations of iron, hydrogen, carbon, oxygen and silicon. The first step of characterization was measuring the optical absorption of all the samples using a UV-NIR fiber spectrometer. Through this procedure it was found that they all showed a strong absorption at 518 nm. Thus, time-resolved differential transmission measurements were conducted at this wavelength using the second harmonic generation (SHG) of a femtosecond ytterbium-doped fiber amplifier (YDFA), mode-locked laser. Relaxation times between 24 and 433 picoseconds were obtained. Finally, four point probe measurements were performed in the order to determine the bulk resistivity of the GaN samples. The measured values are within the order of 106Ω*m for all samples.

Page Count


Department or Program

Department of Electrical Engineering

Year Degree Awarded